The present invention relates to an optical information processing apparatus for recording and reproducing information to and from a record medium by a light beam, and more particularly to an optical information processing apparatus which is suitable to an erasable (rewritable) optical disk capable of recording, reproducing and erasing information.
As a tracking method in an optical information processing apparatus such as optical disk apparatus or optical card apparatus, a push-pull method has been known in which a diffraction light reflected by a guide track (pre-groove) is utilized for tracking. In the push-pull method, it has been known that a track offset is created by the inclination of the disk or the movement of a beam so that the stability of the tracking is disturbed. In order to prevent it, mirror surface portions are provided in the guide track (JP-A-No. 59-19250, U.S. Pat. No. 4,663,751) or wobbled pits are formed (U.S. Ser. No. 845,340). In those methods, a track offset component is detected from a correction mark such as mirror surface or wobbled pits and it is added to or subtracted from a tracking servo system by the guide groove to stabilize the track control.
However, the above techniques do not refer to a problem caused in recording or erasing information by feeding the offset component detected by the correction mark back to the tracking servo system by the guide track.